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    <title>Document</title>
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    <script>
        let arr1 = [1,3,5,7,9];
        let arr2  = [2,4,6,8,10];
        console.log(...arr1);  //展开一个数组
        console.log(arr1);  //输出一个数组

        let arr3 = [...arr1,...arr2] //连接数组
        console.log(arr3);

        // 在函数中使用
        function sum(...numbers){
        return   numbers.reduce((prevalue,currentValue)=>{
                return prevalue+currentValue 
          })
        }
       
        console.log(sum(1,2,3,4));

        // 三点运算符不能展开一个对象
        // let person = {name:'tom',age:18};
        // let person2  = person;
        // // console.log(...person);  //报错，展开运算符，不能展开一个对象
        // person.name = 'jack';
        // console.log(person2.name);  //引用类型的

        // 构造字面量对象时使用展开语法
         let person = {name:'tom',age:18};
        let person2  = {...person};
         person.name = 'jack';
         console.log(person2.name);
         console.log(person2);

        //  复制对象的同时修改属性,合并操作
         let person3 = {...person,name:'jueey',address:'河南'};
         console.log(person3);

    </script>
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